Many medical, food or other products are processed by exposure to doses of high energy radiation. The radiation exposure is used, for instance, to sterilize medical products, extend the shelf-life of foods, inactivate leukocytes in donated blood products or to sexually sterilize certain insect pests. In conjunction with the irradiation of such products it is common to attach human readable irradiation indicators to the products to provide a visual verification that a particular product has passed through the irradiation process and to distinguish irradiated that product from an unirradiated product.
For example, RAD-SURE® irradiation indicators are commonly used to verify irradiation of blood products and STERIN® irradiation indicators are used to verify the irradiation of certain insect pupae subsequently employed in the control of fruit and vegetable pests. Such indicators provide an indication of radiation exposure by employing a radiation sensitive coating in front of human readable indicia. These indicators are printed with the words “NOT IRRADIATED”. The word “NOT” is covered by a radiation sensitive coating that is transparent before irradiation, but is opaque after irradiation. Thus before exposure to radiation the indicia read “NOT IRRADIATED” and after irradiation to a minimum dose of radiation the indicia read “IRRADIATED”.
In the collection, handling, processing, analysis and approval of blood products for transfusion it is common to trace the blood from donation to transfusion through the use of bar coded information attached to the blood bag. Thus a blood unit receives a unique bar-coded serial number upon donation. That serial number is recorded for all samples taken from that blood unit for testing and remains with the blood product as it moves through the system from processing to transfusion. A data management system records the progress of the blood unit so that at any time it is possible to recall and review all information relevant to that blood product. In addition, many other components and supplies used in the donation-processing-testing-donation cycle are also identified and recorded by bar-coded lot numbers. In the event that some component in the cycle is defective it is possible, through the rigorous recording and use of the bar coded information, to easily trace any blood product that has been in contact with the defective component. Such product can then be removed from the system or quarantined for further investigation before it is transfused to a patient.
With respect to irradiated blood products, it is advantageous to have the lot number of any irradiation indicators identified by bar code. If the function of the irradiation indicator is indicated only by human readable indicia, the data management system requires two inputs—a) scanning the bar-code to record the lot number of the irradiation indicator and; b) manual input from the user that the irradiation indicator does, or does not indicate exposure to radiation.